JP5945283B2 - drill - Google Patents

Description

  The present invention relates to a drill that is particularly suitable for processing FRP (fiber reinforced plastics, a composite material of a reinforcing fiber and a resin matrix) and a metal laminate.

  Recently, FRP, especially CFRP (Carbon Fiber Reinforced Plastics), is particularly in the spotlight as a structural material for airplane fuselage and wings. This CFRP may be provided as a plate material having a composite structure in combination with a relatively viscous metal such as aluminum or titanium.

  As the plate material having the composite structure, a metal plate (hereinafter simply referred to as a laminated plate) is used on one surface of CFRP. For example, when forming the fuselage or wing of an airplane, it is necessary to make a hole through which a fastening material such as a bolt or a rivet passes.

  For the drilling, a dedicated drill or a standard drill type general drill proposed by the present applicant in Patent Document 1 below is used.

  The drill of Patent Document 1 has a cutting edge symmetrical to the rotation center from the rotation center to the outer periphery at the tip of the main body, and the cutting edge is at least the rotation center, the intermediate blade connected to the outer end, and the intermediate blade It is composed of three parts of a linear outermost peripheral blade part connected to the outer end, and the tip angle of each blade part is gradually reduced from the rotation center side to the outer peripheral blade part.

JP 2009-172708 A

  When the work material is the above-mentioned laminated plate, the metal layer can be processed from the top so that the thrust load that is disliked in the processing of the single FRP material can be received by the metal layer. For this reason, a hole that satisfies the required quality can be formed even by processing with a standard blade type drill, but this standard blade type drill has a short life and cannot improve productivity.

  On the other hand, the drill of Patent Document 1 makes it possible to process so-called burrs, fluff, flaking, and high-quality holes with less chipping by reducing the thrust applied to the cutting edge on the outer diameter side. ing.

  However, the desired effect can be expected in the processing of a single material of FRP, but in the drilling of the above-mentioned laminated plate, the quality of the hole processed into metal deteriorates. As described above, when the work piece of the laminated plate is arranged with the metal layer on the bottom and a hole is made from above, a cylindrical burr A as shown in FIG. 10 is formed at the outlet of the hole formed in the metal layer. As a result, high-quality holes cannot be obtained.

  Such a problem appears particularly remarkably in the CFRP composite material, but also occurs when the FRP contained in the work material is GFRP (glass fiber reinforced plastics) or the like.

  This invention makes it a subject to provide an effective drill as a solution of the said subject.

In order to solve the above problems, in the present invention, the drill is used for drilling FRP and a metal stack, and has a cutting edge symmetrical to the rotation center from the rotation center to the outer periphery at the tip of the body, The cutting edge is composed of at least two parts of the rotation center side blade part and the outer peripheral side blade part connected to the radial outer end of the rotation center side blade part, and the tip angle of each blade part is the outer periphery from the rotation center side blade part. In the twist drill that gradually decreases to the side blade,
A small-diameter portion having an outer diameter smaller than the drill diameter is provided on the distal end side of the body to form a cutting blade with the tip angle changed in the small-diameter portion, and the small-diameter portion and the original outer diameter behind the small-diameter portion ( A Sarae blade having an inclination angle β with respect to a line perpendicular to the axis of 30 ° or less was provided in a step portion generated between the portion having a drill diameter).

  The FRP and metal overlap plate processing drill has a radial step of the Sarae blade installation portion obtained by the formula {(D−d) / D} where D is the diameter of the drill and d is the diameter of the small diameter portion. It is preferable that the dimension is set to about 0.06 to 0.13 (the step size per radius is ½ of that) by the ratio with the drill diameter.

  Further, the inclination angle β of the Sarae blade was also tested at 45 ° and 60 °, but 30 ° or less, particularly 15 ° or less, was particularly preferable because the quality of the processed hole was excellent. In addition, the inclination angle β of the Sarae blade may be a negative angle. However, a Sarae blade with a negative inclination angle has a sharp outer edge in the radial direction and is liable to be damaged. It's better to make a corner.

  Furthermore, the torsion angle (main torsion angle) of the main part of the torsion groove formed in the drill is set to 5 to 45 °, more preferably 15 to 45 °, and the torsion angle on the tip side of the drill is changed. It is also effective to make it smaller than the main helix angle.

The twist angle of the twist groove may be changed in the small diameter portion. If the twist angle α1 of the small-diameter portion and the main twist angle α2 behind the small-diameter portion are both made constant, the drill can be processed easily. However, as the twist angle α1 itself of the small-diameter portion goes backward from the tip side of the drill, The size can be increased stepwise or gradually. In this structure, it is preferable that the twist angle α1 is smaller than the main twist angle α2 by about 5 ° to 10 °.
Also, a return portion is provided in a part of the twisted groove forming the Sarae blade, and the return angle of the twisted groove in the return portion is made 5 ° to 10 ° smaller than the main twist angle of the twisted groove, or the return portion It is also preferable to set the drill axial width of 0.04D to 0.07D.

  In addition, it is also preferable to form a diamond film on the surface of the body from the viewpoint of improving durability.

  In the drill according to the present invention, a Sarae blade having an inclination angle β of 30 ° or less is provided in a step portion between a tip small diameter portion and a portion having an original outer diameter, and the Sarae blade is formed on a metal such as aluminum. The outer diameter side of the hole to be processed is processed.

  When a sticky metal such as aluminum is machined with a cutting edge having a small tip angle and a low thrust load, a cylindrical burr is more likely to occur at the hole exit. Since the Sarae blade provided in this invention is subjected to a larger thrust load than a general drill, the outer diameter side of the processed hole can be cut off cleanly to the hole exit, thereby providing a high-quality hole without a cylindrical burr. Is obtained.

  In addition, the cutting edge provided on the tip side small diameter part gradually decreases the tip angle from the center of rotation to the blade part on the outer peripheral side, so the outer diameter of the hole processed into FRP by the cutting edge of the small diameter part The side is machined with a small thrust load. After that, the Sarae blade of the stepped part performs the hole expanding process.

  Since the Sarae blade is a blade that increases the thrust load, CFRP and GFRP processing is an inducing factor for delamination, but the installation width (step size) of the Sarae blade is set appropriately. (The installation width in the drill diameter ratio is preferably in the range of 0.06 to 0.13), so that the quality of the hole processed into the FRP is avoided and the hole processed into the FRP is also high quality. Can be secured.

The side view which shows the whole structure of the 1st form of the drill of this invention End view of the tip side of the drill of FIG. The figure which expanded the rotation center part of FIG. Projection view of the blade shape of the drill in FIG. Image showing the diamond coating on the body surface Side view of the tip side of the drill with a constant twist angle of the torsion groove Side view of the tip side of the drill with the twist angle of the twist groove changed at the rear end of the small diameter part The side view which looked at the front end side of the drill of FIG. 7 from the direction rotated 90 degrees from the position of FIG. Sectional drawing which shows the drilling condition by the drill of this invention of the laminated board which made the metal layer down The figure which shows the burr | flash formed in the exit of a processing hole by the hole processing of the laminated board which made the metal layer down. Explanatory drawing of the axial direction return width | variety of the return process part given to the twist groove | channel of the Sarae blade installation part of the drill of this invention Explanatory drawing of the return angle of the return process part given to the twist groove of the Sarae blade installation part of the drill of this invention (arrow X direction view of FIG. 8)

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a stacked plate machining drill according to the present invention will be described below with reference to FIGS. These figures show an application example to a solid drill. The illustrated drill is made of a cemented carbide or the like, and has two cutting edges 3 and 3 having a symmetrical shape at the tip of the body 1 extending from the tip of the shank 2, and a center for reducing the core thickness. It has symmetrical thinning portions 4 and 4, and further has two twisted grooves 5 and 5 on the outer periphery of the body 1.

  The body 1 is provided with a small diameter portion 6 on the distal end side, and a cutting edge 3 is formed in the small diameter portion 6. As shown in detail in FIG. 4, the cutting edge 3 of the exemplary drill includes a rotation center side blade portion 3a, an intermediate blade portion 3b connected to the radially outer end of the rotation center side blade portion, and the intermediate blade portion 3b. It is comprised by 3 parts of the outer peripheral side blade part 3c continuing to a radial direction outer end.

  The tip angle of each blade portion decreases stepwise from the rotation center side blade portion to the outer peripheral side blade portion, so that a so-called three-angle type drill is formed.

  A portion located rearward of the small diameter portion 6 of the body 1 is referred to as a large diameter portion here. The large diameter portion 7 has an original diameter, and a radial step is formed between the large diameter portion 7 and the small diameter portion 6.

  In this invention, the Sarae blade 8 is provided in the level | step-difference part, and there exists the characteristic of invention. The diameter of the large-diameter portion 7 of the body is D, and the diameter of the small-diameter portion 6 is d. The diameter difference between the large-diameter portion and the small-diameter portion, that is, the Sarae blade installation portion obtained by the expression {(D−d) / D}. The radial step size (2S) is set in the range of 0.06 to 0.13 as a ratio to the drill diameter.

  The ratio range was selected for the following reason. That is, if the Sarae region by the Sarae blade 8 is too narrow, as shown in FIG. 9, in the drilling of the stacked plate 20 with the metal layer 21 down, a situation occurs in which the metal layer 21 is crushed without being cut. A cylindrical burr is generated at the hole outlet. By setting the ratio of the radial step size to the drill diameter to be 0.06 or more, the cutting of the metal layer 21 by the Sarah blade 8 is stably performed, the crushing phenomenon is alleviated, and a clean hole is formed.

  In addition, by setting the ratio of the radial step size to the drill diameter to be 0.13 or less, the hole expanding area by the Sarae blade 8 of the pilot hole pre-worked on the FRP 22 by the cutting edge 3 falls within an appropriate range, and the FRP 22 is good. It is avoided that the pilot hole machined into a rough hole is roughened by the hole expansion by the Sarae blade 8.

  The inclination angle β of the Sarae blade 8 (inclination angle with respect to a line perpendicular to the axis of the drill, see FIG. 4) is set to 0 ° or more and 30 ° or less. By setting the inclination angle β to 30 ° or less, it is possible to reduce cylindrical burrs generated at the processing hole outlet in the hole processing with the metal layer down. The inclination angle β was particularly preferably 15 ° or less. The inclination angle β may be a negative angle, but at the negative angle, the radial outer end of the Sarah blade 8 becomes too sharp, causing a problem in strength. For this reason, the lower limit was set to 0 ° or more.

  Further, a connecting portion 9 having a fine back taper of about 0.8 to 2.0 / 100 is provided between the radially outer end of the cutting edge 3 and the starting end of the Sarah blade 8. The connecting portion 9 is not an essential element, but if this is present, the Sarae blade 8 bites into the work material after the processing by the cutting edge 3 is completely completed. The removal of burrs generated in the layer is made more stable.

  In the illustrated drill, the tip angle θ1 of the rotation center side blade portion 3a shown in FIG. 4 is 130 °, the tip angle θ2 of the intermediate blade portion 3b is 70 °, and the tip angle θ3 of the outer peripheral side blade portion 3c is 35 °. Although set, the tip angle is not limited to the exemplified numerical values.

  For example, the tip angle θ1 of the rotation center side blade portion 3a is about 120 ° to 135 °, the tip angle θ2 of the intermediate blade portion 3b is about 70 ° to 100 °, and the tip angle θ3 of the outer peripheral side blade portion 3c is 55 ° to 10 °. Appropriate numerical values can be selected from the range of degrees.

  The application object of the present invention may be a two-angle type drill in which two kinds of tip angles are combined, or a drill in which three or more different tip angles are combined.

  In addition, the thinning portion 4 is preferably overlap thinning as shown in FIG. 3 (a structure in which the thinning groove enters the flank side beyond the center of the drill) because the reduction effect of thrust is high, but is not limited to this. Absent.

  The twist groove 5 has a twist angle of about 5 ° to 45 °. The twist angle is not particularly limited, but it is desired that the cutting edge of the cutting edge is sharp in FRP processing. Therefore, the twist angle is preferably large, and 15 ° to 45 ° is appropriate.

  Further, the torsion angle α of the torsion groove 5 may be constant as shown in FIG. 6, but as shown in FIGS. 7 and 8, the torsion angle α1 in the small-diameter portion 6 on the distal end side is excluded from the small-diameter portion. It is preferable to make it smaller than the torsion angle (main torsion angle α2) of the portion, and this structure can provide the following effects. As described above, the twist angle can be changed in the middle of the length of the twist groove 5 by shaving a part of the groove surface of the twist groove 5.

  Thereby, the chip pocket of a drill front-end | tip part becomes large, and chip discharge | emission property can be improved. Moreover, since the blade angle is increased by reducing the twist angle on the tip side, the strength of the blade edge can be improved. Furthermore, since the rake angle of the cutting edge 3 is reduced, the force for scooping up the work material is reduced, and the occurrence of FRP delamination can be suppressed.

  Thus, when reducing the twist angle in the small diameter part 6, it is preferable to make the twist angle α1 in the small diameter part 6 smaller by about 5 ° to 10 ° with respect to the main twist angle α2. The effect which changed the twist angle can fully be acquired by making the difference into 5 degrees or more. In addition, by setting the difference to 10 ° or less, it is possible to avoid that the thickness (back metal amount) of the cutting edge forming portion becomes too small and the strength is lowered.

  The torsion angle α1 at the distal end side small diameter portion 6 is not necessarily constant. A setting that gradually increases or gradually increases from the drill tip side toward the rear side is also conceivable.

  On the outer periphery of the large-diameter portion 7 of the body, margins 10 are respectively provided at the front edges of the two land portions 12 in the drill rotation direction.

  As another preferred configuration, a diamond coating 11 (see FIG. 5) is provided on the surface of the body 1. The drill having the diamond coating 11 is excellent in life, but the cutting edge tends to be rounded due to the influence of the coating. In addition, the diamond coating 11 increases the coefficient of friction with the work material. For this reason, the generation of burrs at the hole exit of the metal layer of the laminated plate and the metal welding to the drill become more prominent than the drill without the coating.

  Since the drill of this invention is provided with a Sarah blade suitable for metal processing, even if a diamond coating is provided, the generation of burrs and metal welding hardly occur.

  In addition, although the above description gave and demonstrated the solid drill as an example, this invention is applicable also to a blade-tip-exchange-type drill. If a detachable cutting head is mounted on the front end side of the body, and the cutting blade 3 and the Sarah blade 8 are provided on the cutting head, a blade tip type drill can be obtained.

  The blade tip type drill has a smaller number of re-polishing operations than the solid drill for regrinding, but has the advantage that the cutting blade damaged by replacing only the cutting head can be easily and quickly regenerated.

  The problem of the present invention, that is, the problem of the occurrence of burrs at the hole exit of the metal layer of the laminated plate is particularly remarkable in the CFRP laminated plate, but the FRP contained in the work material is GFRP (glass fiber reinforced plastics). ) And the like, the present invention is also effective in processing a GFRP laminate.

  Drill diameter D = 6.375 mm, step size S = 0.2 mm, tip angle θ1 = 130 °, θ2 = 70 °, θ3 = 35 °, diameter of the region with tip angle θ1 = φ3. 5 mm, diameter of the region with tip angle θ2 = φ5.3 mm, diameter of the region with tip angle θ3 = φ6.35 mm, axial dimension L from the tip to the Sarah blade L = 6 mm, inclination angle of the Sarah blade A drill with β = 15 ° and a twist angle of a twist groove of 30 ° was made as a trial product (Invention 1).

The following drill was also prototyped.
Invention 2: Inclination angle β of Sarae blade = 30 °. Other specifications are the same as invented product 1.
Invention 3: Step size S = 0.4 mm. Other specifications are the same as invented product 1.
-Invention 4: Step size S = 0.4 mm, Sarae blade inclination angle β = 30 °. Other specifications are the same as invented product 1.
・ Comparative product 1: No Sarae blade. Other specifications are the same as invented product 1.
-Comparative product 2: Sarae blade inclination angle β = 45 °. Other specifications are the same as invented product 1.

Next, a laminated plate (CFRP 19 mm + aluminum 4 mm = 23 mm) laminated and bonded with a CFRP plate and an aluminum plate using the above sample was processed under the following conditions with the aluminum plate facing down.
Cutting conditions: Machining speed S = 3200 min ⁻¹ , feed f = 0.1 mm / rev

  As a result of this test, the comparative product 1 had a large cylindrical burr at the exit of the processed hole formed in the aluminum plate. Moreover, although the comparative product 2 was not as large as the comparative product 1, the cylindrical burr | flash produced in the exit of the processed hole formed in an aluminum plate.

  On the other hand, the holes processed with Inventions 3 and 4 were clean holes without burrs at the exit. Inventive products 1 and 2 have some cylindrical burrs at the exits of the processed holes formed in the aluminum plate. This seems to be due to the fact that the step size S is insufficient.

  Using the same sample and the same work material as in Example 1, the machining conditions were the same, and a hole was made in the work material with the CFRP plate down. As a result, the comparative product 1 had noticeable peeling and fluffing at the exit of the processed hole formed in the CFRP plate. Although the comparative product 2 was not as large as the comparative product 1, fuzz occurred at the exit of the processed hole formed in the CFRP plate.

  On the other hand, the holes processed with the inventive products 1 to 4 had less fuzz at the exit. Inventive products 3 and 4 were slightly fuzzy, which seems to be because the Sarae blade is a blade more suitable for metal processing than CFRP.

  Inclination angle β of Sarae blade = 15 °, step portion dimension S = 0.5 mm, others are comparative product 3 having the same specifications as invented product 1, and Sarae blade inclination angle β = 30 °, step portion dimension S = 0. A hole was made in the same work material under the same processing conditions as in Example 1 by using a comparative product 4 having the same specifications as that of Invention Product 1 for 5 mm. As a result, in the processing using the comparative products 3 and 4, delamination occurred in the CFRP plate at the laminated interface portion of the aluminum plate. The cause seems to be that the stepped portion dimension S is too large.

  A torsion angle of the torsion groove is set to 25 ° only at the small diameter portion, and a drill having the same specifications as that of Invention 1 is made as a trial product. Using the drill, the same work material is used under the same processing conditions as in Example 1. I made a hole. As a result, a back counter (return) at the CFRP outlet did not occur. This is thought to be due to the fact that the chip pockets near the cutting edge have increased the chip discharge performance.

  The twisting process was performed on the twisting groove (the portion that becomes the rake face of the Sarae blade) of the Sarae blade installation part. The axial return width W of the return portion (see FIG. 11; the axial width of the return portion 5a) was 0.04D, and the twist angle (main twist angle) and return angle γ (see FIG. 12) of the twist groove were changed. Except for the points, holes were made in the same workpiece under the same processing conditions as in Example 1. As a result, when the return angle γ of the torsion groove of the Sarae blade forming part is 5 ° to 10 ° and the torsion angle of the torsion groove of the Sarae blade forming part is 5 ° to 10 ° smaller than the main torsion angle, Generation of delamination could be suppressed, and the strength of the cutting edge and the quality of the machined surface could be improved.

  Tables 1 and 2 show the results of performance evaluation of drills having the main twist angles of 45 ° and 40 ° of the twisted groove in which the angle return is performed on the twisted groove of the Sarae blade forming portion.

  In the same manner as in Example 5, the return processing was performed on the twist groove (portion that becomes the rake face of the Sarae blade) of the Sarae blade installation portion. Except for the point that the return angle γ (see FIG. 12) of the return part is set to 35 ° and the twist angle of the twist groove and the axial return width W (see FIG. 11) of the return part are changed, the same as in Example 1. And drilled holes in the same workpiece under the same processing conditions. As a result, when the return width W in the axial direction of the return portion is set in the range of 0.04D to 0.07D, generation of burrs and delamination can be suppressed, and the strength of the cutting edge and the quality of the machined surface are improved. I was able to.

  Tables 3 and 4 show the results of performance evaluation of drills with main twist angles of 45 ° and 40 ° of the twist groove in this test.

DESCRIPTION OF SYMBOLS 1 Body 2 Shank 3 Cutting edge 3a Rotation center side blade part 3b Intermediate blade part 3c Outer peripheral side blade part 4 Thinning part 5 Torsion groove 6 Small diameter part 7 Large diameter part 8 Sarae blade 9 Joint part 10 Margin 11 Diamond coating 12 Land part D Drill diameter d Small diameter outer diameter θ Tip angle β Slope angle α1 Small angle helix angle α2 Main helix angle W Torsion groove axial return width of the Sarah blade formation part γ Return angle of the twisting groove of the Sarae edge formation part

Claims (7)

A drill used for drilling, having a cutting edge (3) symmetrical to the rotation center extending from the rotation center to the outer periphery at the tip of the body (1), and the cutting edge is at least the rotation center side blade (3a) and It consists of two parts, the outer peripheral side blade part (3c) connected to the radial outer end of the rotation center side blade part, and the tip angle (θ) of each blade part is changed from the rotation center side blade part (3a) to the outer peripheral side blade. In the twist drill that gradually decreases toward the part (3c),
A small-diameter portion (6) having an outer diameter smaller than a drill diameter is provided on the distal end side of the body (1), and the cutting edge (3) with the tip angle changed is formed in the small-diameter portion. A Sarae blade (8) having an inclination angle (β) with respect to a line perpendicular to the axis of 30 ° or less is formed on the step portion formed between (6) and the large-diameter portion (7) having the original outer diameter behind it. set,
The main torsion angle (α2) of the torsion groove (5) formed in the drill is set to 5 to 45 °, and the torsion angle of the torsion groove (5) is set at the axial rear end of the small diameter portion (6). The drill is characterized in that the twist angle (α1) in the small diameter portion (6) is made smaller than the main twist angle (α2) .   When the drill diameter is D and the diameter of the small-diameter portion (6) is d, the radial step size of the Sarae blade installation portion obtained by the expression {(D−d) / D} is 0 as a ratio to the drill diameter. The drill according to claim 1, which is set to 0.06 to 0.13.   The drill according to claim 1 or 2, wherein a diamond coating (11) is formed on the surface of the body (1). The drill according to claim 1 , wherein a main twist angle (α2) of the twist groove (5) is 15 to 45 °. The drill according to any one of claims 1 to 4 , wherein a twist angle (α1) in the small diameter portion (6) is 5 ° to 10 ° smaller than the main twist angle (α2). A return portion (5a) is provided in a part of the twisted groove forming the Sarae blade (8), and the return angle (γ) of the twisted groove in the return portion is determined from the main twist angle (α2) of the twisted groove (5). The drill according to any one of claims 1 to 5, wherein the diameter is also 5 ° to 10 ° smaller. The Sarae part to the return portion of the spiral flute forming the blade (8) and (5a) is provided, according to claim 1 to 5 set the return portion of the drill axis width (W) to 0.04D~0.07D The drill according to any one of the above.

Images